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Nonresonant Multiphoton Ionization of Stark Decelerated Molecules by Femtosecond Laser Pulses

Authors :
Congsen Meng
Zhihui Lü
Xiaowei Wang
Dongwen Zhang
Zengxiu Zhao
Jianmin Yuan
Source :
Chinese Physics Letters. 39:113701
Publication Year :
2022
Publisher :
IOP Publishing, 2022.

Abstract

Nonresonant multiphoton ionization by femtosecond laser pulses can be applied to any molecule virtually, thereby greatly enhancing the scope of Stark decelerated molecules. For comparison, we detect decelerated and trapped ammonia molecules using two different schemes: (i) nonresonant multiphoton ionization using intense femtosecond (fs) pulses in the near infrared, and (ii) resonance-enhanced multiphoton ionization using nanosecond (ns) pulses from a tunable UV laser. The observed number of ions per shot for both schemes is similar. The fs laser detection scheme suffers from an increased background, which can be effectively eliminated by subsequent mass and velocity selection. To determine the detection volume of the ns laser detection scheme, we present measurements in which the decelerated ammonia molecules are bunched to a packet with a longitudinal spread well below ∼100 μm. It is concluded that the detection volume for the ns laser detection scheme is 1.5–2 times larger than that of the fs laser detection scheme.

Subjects

Subjects :
General Physics and Astronomy

Details

ISSN :
17413540 and 0256307X
Volume :
39
Database :
OpenAIRE
Journal :
Chinese Physics Letters
Accession number :
edsair.doi...........e82ed452c3067af116d7815c42f3a3a8